Thanks for humoring me, @slaneman. If there are times when Bono sings, "Live it out," I think it fits the narrative of the song well.
My interpretation is that he is pleading with people to "live out" their beliefs, convictions, and ethics. The music video helps me understand it this way. Those who are "on their knees" are people who claim some sort of overarching belief or ethic - often times through the lens of their given faith structure - and being on one's knees is an image of someone who is praying. Many people claim faith and talk a lot of talk, and will even go so far as to pray for someone or something, but then fail to back up their sentiments or claims with any actionable action. So, the plea here is for those persons to "get up off (their) knees" and do something about whatever it is they are/were praying for/about. Or, to use a more common colloquialism, people often fail to "put footsteps to their prayers."
The song is replete with spiritual language and references - i.e. "catholic blues," "convent shoes," "sermon on the mount," and a bit less specific, but still in the spiritual wheelhouse, "line of grace," etc. And, in that sense, I think Bono is targeting christendom, in a more immediate sense, but I think the message, or application of the message, is more universal and can be applied to anyone who espouses an ethic, but fails to live out their convictions.
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